Searches for the rare hadronic decays $B^0\to p\overline{p}p\overline{p}$ and $B_s^0\to p\overline{p}p\overline{p}$ are performed using proton-proton collision data recorded by the LHCb experiment and corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. Significances of $9.3\sigma$ and $4.0\sigma$, including statistical and systematic uncertainties, are obtained for the $B^0\to p\overline{p}p\overline{p}$ and $B_s^0\to p\overline{p}p\overline{p}$ signals, respectively. The branching fractions are measured relative to the topologically similar normalization decays $B^0\to J/\psi (\to p\overline{p})K^{*0}(\to K^{+}{\pi }^{-})$ and $B_s^0\to J/\psi (\to p\overline{p})\varphi (\to K^{+}{K}^{-})$. The branching fractions are measured to be $\mathcal{B}(B^0\to p\overline{p}p\overline{p})=(2.2\pm 0.4\pm 0.1\pm 0.1)\times {10}^{-8}$ and $\mathcal{B}(B_s^0\to p\overline{p}p\overline{p})=(2.3\pm 1.0\pm 0.2\pm 0.1)\times {10}^{-8}$. In these measurements, the first uncertainty is statistical, the second is systematic, and the third one is due to the external branching fraction of the normalization channel.

• Received 22 November 2022
• Revised 1 March 2023
• Accepted 23 March 2023

DOI:https://doi.org/10.1103/PhysRevLett.131.091901

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